Most of our work has focused on the biosynthesis and processing of the glycoprotein (G) encoded by vesicular stomatitis virus (VSV). We have shown that G is a transmembrane protein immediately after its synthesis; facing the cytoplasmic face of the endoplasmic reticulum are 30 amino acids from the carboxyl-terminus of the molecule, while the bulk of the polypeptide and both asn-linked "core" carbohydrate chains are facing the lumen. Each carbohydrate chain, containing NAcG1n and Man, is added as a unit to the nascent chain at a prescribed time. These studies were facilitated by the development of a cell-free system in which core glycosylation and transmembrane insertion of G are achieved. Further, we could show that glycosylation of G is not essential for normal transmembrane insertion. The binding of G mRNA to the er could be shown to be due only to the nascent G chain, presumably the NH2-terminus, and not to direct binding by the mRNA. Additional studies have explored in more detail the relative rates of initiation of translation by the different VSV mRNAs, and the role fo the 5' "cap" in in vitro translation.